package cn.ywang.spring.orm.framework;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.math.BigDecimal;
import java.sql.Date;
import java.sql.Timestamp;
import java.util.*;

/**
 * @author BeatificWang
 * @date 2019/5/4 23:41
 */
public class ClassMapping {
	private ClassMapping() {
	}

	static final Set<Class<?>> SUPPORTED_SQL_OBJECTS = new HashSet<>();

	static {
		//只要这里写了的，默认支持自动类型转换
		Class<?>[] classes = {
				boolean.class, Boolean.class,
				short.class, Short.class,
				int.class, Integer.class,
				long.class, Long.class,
				float.class, Float.class,
				double.class, Double.class,
				String.class,
				Date.class,
				Timestamp.class,
				BigDecimal.class
		};
		SUPPORTED_SQL_OBJECTS.addAll(Arrays.asList(classes));
	}

	static boolean isSupportedSQLObject(Class<?> clazz) {
		return clazz.isEnum() || SUPPORTED_SQL_OBJECTS.contains(clazz);
	}

	public static Map<String, Method> findPublicGetters(Class<?> clazz) {
		Map<String, Method> map = new HashMap<String, Method>();
		Method[] methods = clazz.getMethods();
		for (Method method : methods) {
			if (Modifier.isStatic(method.getModifiers())) {
				continue;
			}
			if (method.getParameterTypes().length != 0) {
				continue;
			}
			if (method.getName().equals("getClass")) {
				continue;
			}
			Class<?> returnType = method.getReturnType();
			if (void.class.equals(returnType)) {
				continue;
			}
			if (!isSupportedSQLObject(returnType)) {
				continue;
			}
			if ((returnType.equals(boolean.class)
					     || returnType.equals(Boolean.class))
					    && method.getName().startsWith("is")
					    && method.getName().length() > 2) {
				map.put(getGetterName(method), method);
				continue;
			}
			if (!method.getName().startsWith("get")) {
				continue;
			}
			if (method.getName().length() < 4) {
				continue;
			}
			map.put(getGetterName(method), method);
		}
		return map;
	}

	public static Field[] findFields(Class<?> clazz) {
		return clazz.getDeclaredFields();
	}

	public static Map<String, Method> findPublicSetters(Class<?> clazz) {
		Map<String, Method> map = new HashMap<String, Method>();
		Method[] methods = clazz.getMethods();
		for (Method method : methods) {
			if (Modifier.isStatic(method.getModifiers())) {
				continue;
			}
			if (!void.class.equals(method.getReturnType())) {
				continue;
			}
			if (method.getParameterTypes().length != 1) {
				continue;
			}
			if (!method.getName().startsWith("set")) {
				continue;
			}
			if (method.getName().length() < 4) {
				continue;
			}
			if (!isSupportedSQLObject(method.getParameterTypes()[0])) {
				continue;
			}
			map.put(getSetterName(method), method);
		}
		return map;
	}

	public static String getGetterName(Method getter) {
		String name = getter.getName();
		if (name.startsWith("is")) {
			name = name.substring(2);
		}
		else {
			name = name.substring(3);
		}
		return Character.toLowerCase(name.charAt(0)) + name.substring(1);
	}

	private static String getSetterName(Method setter) {
		String name = setter.getName().substring(3);
		return Character.toLowerCase(name.charAt(0)) + name.substring(1);
	}
}
